Method of reducing sulfids.



n. F. BACON v METHOD OF REDUCING SULFIDS. APPLICATION FILED JAN. I5,1913.

' 'Patent ed Oct. 23,1917.

N N v \u RAYMOND F. BACON, 0F PITTSBURGH,

orrrcn.

PENNSYLVANIA, ASSIGNOR, BY MESNE ASSIGN- -MENTS, TO METALS RESEARCHCOMPANY, OF NEW YORK, N. Y., A. CORPORATION OFMAIN'E.

To all whom it may concern: i

residing at Nicholson street, Pittsburgh, Allegheny county, State ofPennsylvania, have invented certain new and useful Improvements inMethods of Reducing Sulfids; and I do hereby declare the following to bea full, clear, and exact description of the invention, such as willenable others skilled in the art to which it appertains to make and usethe same.

The present invention is based upon the discovery that when the sulfidsof silver,

mercury, arsenic, antimony and platinum are caused to reactwith ahydrocarbon, at a suitable and sufficiently low temperature, the metalof the sulfid will be recovered in the metallic state, and hydrogensulfid as such, utili'zable for various purposes in the art, will alsobe recoverable.

Among the sulfids above enumerated as feasible for the practice of theinvention, it is found that some of them react more readily and atlower. temperatures than others, and that the physical state of thesulfid is an important factor in this regard. In general, it may be saidthat precipitated sulfids react more readily and completely, under thesame conditions, than natural sulfids, and the precipitated sulfids areto some degree approximated in efficiency in this regard by naturalsulfids which have first been finely ground or otherwisefinelycomminuted'. I

The process is also applicable, as above indicated, to certain mineralscontaining the available sulfids, as, for instance, cinnabar. Cinnabarreacts quite easily and at comparatively low temperatures, and, whencinnabar is reduced in accordance with the invention, if the temperatureis suflicient to volatilize the mercury, the released mercury vapordistils over and may be collected in a suitable condenser.

In so far as the reduction of the metallic sulfids is concerned, it isnot necessary to keep the temperature below the dissociation point ofhydrogen sulfid. Where hydrogen sulfid is to be produced, however, itshould be borne in mind, in controlling the temperature of the reactionthat hydrogen sulfid begins to dissociate at about 400 C. and that thedissociation amounts to about 8% at 500 C. and assumes increasingimpormn'rnon or nnnocrne sonrrns.

Specification of Letters Patent.

Patented oct. 23, 1917.

Application filed January 15, 1913. Serial No. 742,219,

tance at higher temperatures. It is therefore desirable, in so far asthe production of hydrogen sulfid is concerned, to maintain thetemperature relatively low, and,

.in general, not to exceed 500 0. So also, inasmuch as the sulfids arereduced in the practice of the invention at temperatures below 500 (1,it would not be economical to proceed at any higher range oftemperature. V

The sulfid may be charged into a suitable receiver, which mayconveniently have the form and dimensions of an ordinary still, adaptedto be heated, as, for instance, ex-

ternally by direct firing, in the usual manner, or internally, and whichis provided With the necessary means for admitting the sulfid charge,for supplying the hydrocarbon, and for the I products of the treatmenteither continuously or intermittently, and also with means forconducting ofi' the hydrogen sulfid to the place of storage,condensation, or use. If the sulfid charged contains a large quantity ofmoisture, .as, forinstance, in the case of a wet precipitate, thecontaining vessel should have a sufficient capacity, with respect to thecharge, to take care of such foaming as is incident to the operation,or, any su table means may be provided to suppress the foam or toprevent it from removal of the residual rising to too high a-level abovethe upper surfaceof the charge; as, for instance, one or more air jetsof high pressure may be directed upon the forming foam layer so as tobreak it up and release the imprisoned gases or vapors. So also, inorder to prevent the condensation and ceptacle and charge'of any waterthat has been driven ofl in the form of steam during the operation, thestill or receptacle may be provided, in its interior and at the upperpart thereof with a suitable insert through which the gases and vapors,including the hydrogen sulfid and steam, may freely pass on their way tothe exit pipe of the still and which, by reason of its location, is atsuch a temperature as to intercept and reconvert into steam any waterwhich, condensing out of the escaping vapors would tend to return to thecharge.

When a solid or liquid hydrocarbon 'is employed, it may either be mixedwith the sulfid and charged therewith into the receiving vessel orstill, or, it may be adreturn to the re- 1 mitted into the upper part ofthe vessel and permitted to drop upon the heated sulfid. In practice, itis usually preferable to thus admit the hydrocarbon upon the top of thecharge, rather than to mix it therewith in the first instance, for thereason that by dropping the hydrocarbon upon the top of the charge, aquantitative reduction of the sulfid can be effected with a lessersupply of hydrocarbon, so as to reduce, and in some instances, topractically avoid the presence in the still at the termination of theoperation of any large quantity of hydrocarbon to be thereafterrecovered by distillation. It will usually be desirable to employ anamount of hydrocarbon somewhat in excem of that theoretically requiredfor the reaction.

lt is also feasible to practise the invention by showering the sulfidthrough an atmosphere of hydrocarbon vapor, say vaporized mineral oil; aconvenient mode of thus showering the sulfid through the mineral oilvapor may consist, for instance, of a rotatory horizontal or inclinedcylinder, suitably heated, and provided with means for admitting themineral oil vapor at one 1 end thereof and allowing the volatileprodnets of the reaction to take their exit at the other end, and beingfurther provided with longitudinal ledges projecting radially inward andadapted to raise the copper sulfid constituting the charge of the rotarycylinder and permitting it to drop, as will be readily understood.

While, as hereinbefore indicated, the in- 1 Y vention isnot restrictedto the use of any particular hydrocarbon, it is found feasible,convenient, and economical, in practice, to use what are known generallyin the arts, as hydrocarbon residues, as, for instance, oils from whichthe lighter and more valuable distillates, such as gasolene, kerosene,and

the lighter lubricating oils have been driven off. The hydrocarbonresidues thus obtain able from the natural petroleums and other oilshaving a similar composition such as shale oils, are entirely adapted tothe purpose, and may be specified as illustrative of those which mayfind ready acceptance for commercial uses; so also, there are availablefor the uses of the invention naphthalene, and substances which, onheating, give I considerable quantities of hydrocarbons, as, forinstance, asphalts and bitumens (natural and artificial) coal tar, watergas tar, wood resins, and resin 011. ,Of course, any of the morevaluable hydrocarbon distillates may be used where the question of costis of less importance.

In the, practice of the invention, it is found that the reduction ofprecipitated mercury sulfid begins to take place at a relatively low,temperature, somewhere between 50 C. and 100 C. It proceeds more rapidlyat higher temperatures, and the process may be conducted to specialadvantage at temperatures representing the boiling point of thehydrocarbons usually employed,that is to say, temperatures ranging from300 C. to 360 0., which will represent approximately the usualcommercial temperatures. Inasmuch as the dissociation of hydrogen sulfidbegins at about 400 C. and becomes increasingly important at highertemperatures, it will be preferable to restrict the temperaturesaccordingly permitting them to rise above say 500 so that there may beno material loss in the recovery of the hydrogen sulfid where thatrecovery is of particular importance, as will usually be the case. I

In the accompanying drawing'is illustrated apparatus of a type adaptedfor the practice of the invention although it-will be understood thatthe illustrationis merely not I representative of many arrangementswhich nation of the reaction period, it may be placed upon trunnions, asindicated, so lo cated with respect to the closable door 9 that thesolid products of the reaction may be discharged into any suitableconveyer atthe end of the reaction. lhese solid products of the reactionwill consist mainly of the carbon of the. decomposed hydrocarbonassociated with the reduced metal, unless the latter has beenvolatilized and distilled OK in the operation. The carbon thusassociated with the metal may be separated therefrom in any suitable orconvenient manner, or, if desired, it may be used as the fuel or a partof the fuel for melting the metal.

E indicates a suitable receptacle for supplying the hydrocarbon to thereaction vessel orv still D. The sulfid to be reduced will be chargedthrough the closable door 9. When a wet precipitateis used or when thesulfid is otherwise in a moist condition, so that the formation of foamwill be an'incident of the operation, high pressure air jets i may beconnected withthe still, as indicated, and may be supplied with air inany suitable ,manner, as, for instance, by the pump J So also, when theinsert hereinbefore referred to conveniently consist of a structure 70of aluminum or other suitable material, adapted to be raised to asufficient heat by the escaping hydrogen sulfid and accompanying vaporson their way to the exit pipe 0 of the vessel D, whereby, ashereinbefore explained,

is employed, it may course, be understood that the several pipes servingthe a paratus may be provided with suitable regu shown, and withsuitable flexible connections and couplings to permit the tiltingof thevessel D; when desired.

What I claim is":

1. The method of reducing the sulfids of silver, mercury, arsenic,antimony and platinum, which comprises reacting upon the sulfid in anon-molten condition to reduce it to metal by means of ahydrocarbon andin a non-oxidizing atmosphere; substantially as described.

2. The method of reducing the sulfids of silver, mercury, arsenic,antimony and platinum, which comprises reacting upon the sulfid in anon-molten condition to reduce it to metal by means of.,a hydrocarbon ina non-oxidizing atmosphere and at a, relatively low temperature;substantially as described.

3' The method of reducing the sulfids of silver, mercury, arsenic,antimony and platinum, which comprises reacting upon the sulfid in anon-molten. condition to reduce it to metal by means of a hydrocarbon atthe boiling point of said hydrocarbon; substantially as described,

4. The method of reducing the sulfids of silver, mercury, arsenic,antimony and platinum, which comprises reacting upon the sulfid in anon-molten condition to reduce it to metal by means of a hydrocarbon ata temperature not above 500 0.; substantially as described.

5. The method of reducing the sulfids of ating or controlling cocks assi lver, mercury, arsenic, antimony and platinum, which comprisesreacting upon the sulfid in a non-molten condition by means of ahydrocarbon under conditions adapted to duction. of sulfid and theformation of hydrogen sulfid; substantially asdescribed.

7. The method of reducing the sulfids of silver, mercury, arsenicantimony and platinum, which comprises dropping a hydrocarbon upon aheated body of the metallic sulfid in a non-molten condition, under conditions adapted to reduce the sulfid to metal; substantially asdescribed.

8. The method of reducing the sulfids of silver, mercury, arsenic,antimony and platinum, which comprises dropping a liquid hydrocarbonupofixa heated body of the me-- tallic sulfid in the form I underconditions adapted to reduce the sulfid to metal; substantially asdescribed.

In testimony whereof I aifix my signature, in presence of two witnesses.

RAYMOND F. BACON.

Witnesses:

M. A. BILL, VINCENT SARAREBE.

of a precipitate, and

